A students' union, student government, free student union, student senate, students' association, guild of students or government of student body is a student organization present in many colleges, universities, and high schools. In higher education, the students' union is often accorded its own building on the campus, dedicated to social, organizational activities, representation and academic support of the membership.
In the United States, student union many times only refers to a physical building owned by the university with the purpose to provide services for students without a governing body also referred to as a student activity center. Outside the United States, student union and students' union refer to a representative body.(Wikipedia)